What city is ZIP code 57521?

ZIP code 57521 is in Belvidere, SD (Mellette County).

What county is ZIP code 57521 in?

ZIP code 57521 is mostly in Mellette County, South Dakota.

How many people live in ZIP code 57521?

About 314 people live in the 57521 ZIP Code Tabulation Area, based on American Community Survey 5-year estimates.

Checked Oct 26, 2026

ZIP Code 57521

Belvidere, SD, Mellette County

Population

314

Land area

427.9sq mi

People per sq mi

City

Belvidere

ZIP 57521 and nearby ZIP codes

Full map

ZIP 57521 at a glance

ZIP 57521 (Belvidere) is 94% less dense than South Dakota as a whole.

Local data for ZIP 57521

Counts from official public data

Economy and federal money

Businesses, pandemic loans and political donations

Details

PPP loans

$636K

40 loans

Campaign donations

$1,600

6% D, 63% R, 2026 cycle

PPP loans in this ZIP

Environment and hazard risk

ZIP 57521, from FEMA, NOAA and EPA

Full report

Natural hazard risk

Very Low

Top: wildfire

Storm events since 1996

461

Countywide, mostly hail

July high / Jan low

90° / 12°F

20.4 inches of rain a year

Hazards, floods and storm history Check a flood zone

Health statistics

Share of adults in ZIP 57521, CDC PLACES estimates

All 40 measures

Obesity

41.9%

U.S. 33.3% +8.6 pts

Diabetes

18.6%

U.S. 12.1% +6.5 pts

Smoking

26.6%

U.S. 12.8% +13.8 pts

Uninsured (18-64)

13.0%

U.S. 11.1% +1.9 pts

Frequently asked questions

What city is ZIP code 57521?: ZIP code 57521 is in Belvidere, SD (Mellette County).
What county is ZIP code 57521 in?: ZIP code 57521 is mostly in Mellette County, South Dakota.
How many people live in ZIP code 57521?: About 314 people live in the 57521 ZIP Code Tabulation Area, based on American Community Survey 5-year estimates.

Source: U.S. Census Bureau (ZIP Code Tabulation Areas, American Community Survey) · Data as of 12/31/2023. ZIP Code Tabulation Areas closely match, but are not identical to, USPS ZIP code delivery areas.